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Full text of "The manufacture and properties of iron and steel"

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METALLURGY OF IRON AND STEEL.
inlet valve and the reversing valve are separate and the inlet valve is r'emoved' from all exposure to heat. This system was devised more especially for oil gas or where crude oil was the fuel, since under these conditions it is necessary that the chamhers at the outer end should be at a high temperature in order to maintain the oil in a. state of vapor. This necessitates a high temperature throughout the whole length of the chamber and an ordinary valve will not stand this temperature without excessive leakage and warping.
FIG. VIII-H.—REVEHSING VALVES AT STEELTON.
Horizontal Section.
A, air inlet; B, J9, air chambers; C, stack; D, air reversing valve; E, JE, gas inlets; FI F, gas chambers: JET, stack damper for air; J, stack reversing valve for gas; K, flue from reversing valve to stack; L, stack damper for gas; JV, 2V, water-cooled valve seats
Such a complicated arrangement is not necessary with coal gas if the chambers are of sufficient capacity. A perfect valve should not warp if it gets hot, and should not leak if coated with tar or soot, and should hot shut up by an accumulation of soot. No valve fills all these conditions, but Fig. VIII-I shows a Forter valve, which is, perhaps, as good as any in being easily manipulated and simple in construction. It is open to the objection that the gas is exposed to water and carries a great deal of steam into the furnace.
SEC. Vlllh.—Regulation of the temperature.—The temperature of the interior of the furnace and of the metal is estimated by the